Stable selenium sulphide and method for its preparation



BIRGER W. NORDLANDER, or soHENEoTAnY, NEW YORK, AssIenoR To Ga ma TRIO COMPANY, AOORPORATION OF NEW YORK Patented May 24, 1932 STABLE SELENIUM SULPHIDE'AND M THOD ron ITs rn PARATIon No Drawing. Original application filed March 28, isease r al No. 350,836. Divided and this application-i.

filed March 20, 1930. Serial No. 437,619.

This application is a division of my copending application, Serial No. 350,836, filed March 28, 1929, which in turn is a continuation in part of my application, Serial No.

5 82,883, filed January 21, 1926, and which is now Patent 1,711,742, granted May 7, 1929, both the copending application and the patent being assigned to the same assignee as in the present application. 4 The present invention relates to a stable, chemically active compound of selenium sulphide and the process of preparing the same.

In the above named patent I described a means for detecting mercury vapor in a gas by the use of selenium sulphide. In that case I also'set forth several methods of preparing this compound. I have found that selenium found that when hydrogen sulphide is passed into a solution of selenious acid, a yellow S01 and a precipitate of a yellowish red. color, having aplastic consistency are formed together. Completereac'tion does not seem to occur since the solutionformed always contains unchanged selenious acid no matter how long the hydrogen sulphide is allowed to act.

The precipitate is very voluminous and much of the acid solution is adsorbed. In this plas-.

tic form the preciptate is very unstable,espe cially when heated or exposed to light and a is chemically not active. i Q

I- have succeeded in preparing selenium V 3*sulphide, of a definite composition corresponding to the formula S 3 which is h me chemlcally and chemically extremely active.-

Such a product has been kept for years without losing its activity; I

One method of preparingthis compound is as follows: Asolutlon of aluminum chlo-= ride containing about 100 milligrams of aluminum per liter is saturatedwith hydrogen sulphide at room temperature,-prefer' ably in a-fiask that is partly closed inorder to retain the atmosphere of the gas-above, the liquid and thus p'romote its absorption byv the solution during the reaction. Vigorous mechanical stirring is also desirableffor the same purpose. While continuing the cur' rent of'hydro'gen sulphide, normal selenious' acid solution is slowly addeddelivering below the surface of the liquid in the flask. At? first a yellowish solis formed which very: A soon, as the concentration increases, is con-" verted to a yellow flocculent precipitate which readily separates; out from the solution. A moderate temporary excess of the acid will form sol which q'uickly clears up if the additionisstopped for the'tima- The operation should 'be carefully watched 'to j keep the hydrogens'ulphide inexcess. The. aluminum chloride acts as a coagulant for, a the sulphide." Other coagulants'may be used 1 V for the same purpose, and as an example, barium chloride maybe mentioned. 1. The. re-s, action proceeds quantitatively according to the formula. 2I-I S+H SeO3 'S,eS +3HZOQ The precipitate is filtered, washed anddried It is a fine yellowpowder and'canvbe driedl on afsteam bath without turning red.

"In accordance with another method of prei i paring thisicompound of solenium sulphide, sulphur andselenium aremixedtogetherin the proportion of onemolecular weight 'of" ,7 selenium to two molecular weights ofsulphur, V I and the mixture heated to aboi'1t"2251 Cf A union takes place" sothat agcherry red melt V,

of-selenium sulphideSeSgis formed; 'When' 1 cooled-downto room temperature it forms a a black plastic mass, plastic in character like rubber. It will retain this condition for several days, butwillthen gradually go over into a hard brittle state so that it can be ground up to form an orange red powder with a melting point of about 100 C. This conversion'is accelerated by heat andif the 'massi's kept just below the melting point, say about80 to 90 C., a conversion takes place in a considerably, shorter period of time, I about ahalf hour. Ihe plastic form' isinac tive but the heat treatment changes it over to the active form.

' Selenium sulphid'e prepared by either of these methods is stable and chemically active and is always of definitecomposition. If, in

" 1,860,386 I I Q it is converted to the active state. v

5. The 'method of producing a: stable chemically active selenium sulphide which;

consists in melting together one molecular resulting mass belowthe melting point untilf I weight of selenium with two molecular weights of sulphur, heating the resulting mass at about 809909 C. until it is converted 1 to the active state, and finally converting the so treatedmass into powdered form,'

In witness whereof I' have hereunto set my 7 hand this 18thday of March, 1930.

it the second method outlined above, other'proportions of selenium and sulphur are used, c 1 the resulting powder [will be a mixtureof stable, chemically active selenium sulphide in i f fln exces's pfsulphur or selenlum, as the case U maybe.

The term StabIe herein to the selenium sulphide produced in accordance with the present inventiondenotes that the compoundis stable to such agencies asheat and light anddenotesalso that theproduct ofllthe present invention is notv decomposed bysuch agencies'but retains its composition,

th'atxis the sulphur and selenium fre'1nain represented by theformula SeS t "chemically, combined having the composition -1Thertermfchemically active as applied to V the selenium sulphideproduced the presmt invention denotes that the compound is reactive chemically;- with substances with which ordinary mixtures of selenium and sulphuror compositions of seleniumandsulphur not prepared bythe methods ofthe present invention are substantiallynot reactive.

What I'cla-im as newand desire to secure by Letters Patent of the United States, is: 1. The Vmethod of producing a stable, chemicallyactive selenium sulphide which comprises the steps of; combining, selenium and sulphur at about 225 C. and converting '7 the combined mass into the chemically active 7 v ,.'2-..Theq method "of producing ca stable, V I l form. V

chemically active seleniumv sulphide which comprises the steps ofm'eltingtogether sele- V V nium' and sulphur, and converting the co 7 V binediinass into the chemically active form. V

The/method of producing a, stable,

chemicallvactive selenium sulphide which 7 comprises the steps of melting togetherselenium "and sulphur and heating the resulting mass below the melting point until it is con vertedto the active state.

7 Ar'TheLmethod of producing a stable, v j I chemically active selenium sulphide which 7 "comprises thesteps :of melting to th one VBIRGER'HW. NonnnA nER.

' molecular weightiofselenium with, two'mo-i t lecular weights of wsulphurand;heatingthe v I 

